/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.drools.ruleunits.impl;

import java.util.HashMap;
import java.util.Map;

import org.drools.ruleunits.api.DataSource;

public interface AssignableChecker {

    boolean isAssignableFrom(Class<?> source, Class<?> target);

    static AssignableChecker create(ClassLoader classLoader) {
        return create(classLoader, classLoader != DataSource.class.getClassLoader());
    }

    static AssignableChecker create(ClassLoader classLoader, boolean classLoaderSafe) {
        return classLoaderSafe ? new ClassLoaderSafeAssignableChecker(classLoader) : DummyAssignableChecker.INSTANCE;
    }

    enum DummyAssignableChecker implements AssignableChecker {

        INSTANCE;

        @Override
        public boolean isAssignableFrom(Class<?> source, Class<?> target) {
            return source.isAssignableFrom(target);
        }
    }

    class ClassLoaderSafeAssignableChecker implements AssignableChecker {
        private final ClassLoader classLoader;
        private final Map<String, Class<?>> classes = new HashMap<>();

        public ClassLoaderSafeAssignableChecker(ClassLoader classLoader) {
            this.classLoader = classLoader;
        }

        @Override
        public boolean isAssignableFrom(Class<?> source, Class<?> target) {
            return classes.computeIfAbsent(source.getCanonicalName(), name -> {
                try {
                    return classLoader.loadClass(name);
                } catch (ClassNotFoundException e) {
                    return source;
                }
            }).isAssignableFrom(target);
        }
    }
}
